-Removed some extraneous logging
-Increased frequency of UDP keepalive pulses from 1/sec to 4/s
-Increased frequency of resending lost packets from every 2 seconds to every second
-Decreased threshold for lost connection from 5 seconds to 2 seconds
-Fixed a bug that caused ACKs not to be correctly sent in some situations
-Throw an exception if HandleIO is called on a client socket with no active connection.
-Fixed dangling pointer when client socket is closed